Auto-calibrating receiver and methods for use therewith

ABSTRACT

A voice, data and RF integrated circuit includes a processing module that generates at least one control signal that indicates a receive calibration mode. An RF transmitter generates a transmit signal that includes a first calibration signal when the at least one control signal indicates the receive calibration mode. An RF receiver receives a received signal that includes the first calibration signal and generates at least one receiver equalization parameter for equalizing the RF receiver in response to receiver feedback signals, when the at least one control signal indicates the receive calibration mode.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

This invention relates generally to wireless communications systems andmore particularly to radio transceivers used within such wirelesscommunication systems.

2. Description of Related Art

Communication systems are known to support wireless and wire linecommunications between wireless and/or wire line communication devices.Such communication systems range from national and/or internationalcellular telephone systems to the Internet to point-to-point in-homewireless networks. Each type of communication system is constructed, andhence operates, in accordance with one or more communication standards.For instance, wireless communication systems may operate in accordancewith one or more standards including, but not limited to, IEEE 802.11,Bluetooth, advanced mobile phone services (AMPS), digital AMPS, globalsystem for mobile communications (GSM), code division multiple access(CDMA), local multi-point distribution systems (LMDS),multi-channel-multi-point distribution systems (MMDS), radio frequencyidentification (RFID), and/or variations thereof.

Depending on the type of wireless communication system, a wirelesscommunication device, such as a cellular telephone, two-way radio,personal digital assistant (PDA), personal computer (PC), laptopcomputer, home entertainment equipment, RFID reader, RFID tag, et ceteracommunicates directly or indirectly with other wireless communicationdevices. For direct communications (also known as point-to-pointcommunications), the participating wireless communication devices tunetheir receivers and transmitters to the same channel or channels (e.g.,one of the plurality of radio frequency (RF) carriers of the wirelesscommunication system or a particular RF frequency for some systems) andcommunicate over that channel(s). For indirect wireless communications,each wireless communication device communicates directly with anassociated base station (e.g., for cellular services) and/or anassociated access point (e.g., for an in-home or in-building wirelessnetwork) via an assigned channel. To complete a communication connectionbetween the wireless communication devices, the associated base stationsand/or associated access points communicate with each other directly,via a system controller, via the public switch telephone network, viathe Internet, and/or via some other wide area network.

For each wireless communication device to participate in wirelesscommunications, it includes a built-in radio transceiver (i.e., receiverand transmitter) or is coupled to an associated radio transceiver (e.g.,a station for in-home and/or in-building wireless communicationnetworks, RF modem, etc.). As is known, the transmitter includes a datamodulation stage, one or more intermediate frequency stages, and a poweramplifier. The data modulation stage converts raw data into basebandsignals in accordance with a particular wireless communication standard.The one or more intermediate frequency stages mix the baseband signalswith one or more local oscillations to produce RF signals. The poweramplifier amplifies the RF signals prior to transmission via an antenna.

As is also known, the receiver is coupled to the antenna through anantenna interface and includes a low noise amplifier, one or moreintermediate frequency stages, a filtering stage, and a data recoverystage. The low noise amplifier (LNA) receives inbound RF signals via theantenna and amplifies then. The one or more intermediate frequencystages mix the amplified RF signals with one or more local oscillationsto convert the amplified RF signal into baseband signals or intermediatefrequency (IF) signals. The filtering stage filters the baseband signalsor the IF signals to attenuate unwanted out of band signals to producefiltered signals. The data recovery stage recovers raw data from thefiltered signals in accordance with the particular wirelesscommunication standard.

Calibration of both receivers and transmitters can be an issue. Phase,frequency timing or gain errors can adversely affect the performance ofreceivers and transmitters. Calibration of these devices during assemblycan be time consuming, costly and not reflect the actual operatingconditions of these devices when they are installed. Further limitationsand disadvantages of conventional and traditional approaches will becomeapparent to one of ordinary skill in the art through comparison of suchsystems with the present invention.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to apparatus and methods of operationthat are further described in the following Brief Description of theDrawings, the Detailed Description of the Invention, and the claims.Other features and advantages of the present invention will becomeapparent from the following detailed description of the invention madewith reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram of a wireless communication systemin accordance with the present invention.

FIG. 2 is a schematic block diagram of a wireless communication systemin accordance with the present invention.

FIG. 3 is a schematic block diagram of a wireless communication device10 in accordance with the present invention.

FIG. 4 is a schematic block diagram of a wireless communication device30 in accordance with the present invention.

FIG. 5 is a schematic block diagram of an RF transceiver 125 inaccordance with the present invention.

FIG. 6 is a schematic block diagram of a transmitter equalization module180 in accordance with an embodiment of the present invention.

FIG. 7 is a schematic block diagram of a receiver equalization module184 in accordance with an embodiment of the present invention.

FIG. 8 is a schematic block diagram of an RF transceiver 125 inaccordance with a further embodiment of the present invention.

FIG. 9 is a schematic block diagram of a transmit/receive switch 175 ina transmit mode in accordance with a further embodiment of the presentinvention.

FIG. 10 is a schematic block diagram of a transmit/receive switch 175 ina receive mode in accordance with a further embodiment of the presentinvention.

FIG. 11 is a schematic block diagram of a transmit/receive switch 175 ina receiver calibration mode and transmitter calibration mode inaccordance with a further embodiment of the present invention.

FIG. 12 is a flowchart representation of a method in accordance with anembodiment of the present invention.

FIG. 13 is a flowchart representation of a method in accordance with anembodiment of the present invention.

FIG. 14 is a flowchart representation of a method in accordance with anembodiment of the present invention.

FIG. 15 is a flowchart representation of a method in accordance with anembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of an embodiment of a communicationsystem in accordance with the present invention. In particular acommunication system is shown that includes a communication device 10that communicates real-time data 24 and/or non-real-time data 26wirelessly with one or more other devices such as base station 18,non-real-time device 20, real-time device 22, and non-real-time and/orreal-time device 24. In addition, communication device 10 can alsooptionally communicate over a wireline connection with non-real-timedevice 12, real-time device 14 and non-real-time and/or real-time device16.

In an embodiment of the present invention the wireline connection 28 canbe a wired connection that operates in accordance with one or morestandard protocols, such as a universal serial bus (USB), Institute ofElectrical and Electronics Engineers (IEEE) 488, IEEE 1394 (Firewire),Ethernet, small computer system interface (SCSI), serial or paralleladvanced technology attachment (SATA or PATA), or other wiredcommunication protocol, either standard or proprietary. The wirelessconnection can communicate in accordance with a wireless networkprotocol such as IEEE 802.11, Bluetooth, Ultra-Wideband (UWB), WIMAX, orother wireless network protocol, a wireless telephony data/voiceprotocol such as Global System for Mobile Communications (GSM), GeneralPacket Radio Service (GPRS), Enhanced Data Rates for Global Evolution(EDGE), Personal Communication Services (PCS), or other mobile wirelessprotocol or other wireless communication protocol, either standard orproprietary. Further, the wireless communication path can includeseparate transmit and receive paths that use separate carrierfrequencies and/or separate frequency channels. Alternatively, a singlefrequency or frequency channel can be used to bi-directionallycommunicate data to and from the communication device 10.

Communication device 10 can be a mobile phone such as a cellulartelephone, a personal digital assistant, game console, personalcomputer, laptop computer, or other device that performs one or morefunctions that include communication of voice and/or data via wirelineconnection 28 and/or the wireless communication path. In an embodimentof the present invention, the real-time and non-real-time devices 12, 1416, 18, 20, 22 and 24 can be personal computers, laptops, PDAs, mobilephones, such as cellular telephones, devices equipped with wirelesslocal area network or Bluetooth transceivers, FM tuners, TV tuners,digital cameras, digital camcorders, or other devices that eitherproduce, process or use audio, video signals or other data orcommunications.

In operation, the communication device includes one or more applicationsthat include voice communications such as standard telephonyapplications, voice-over-Internet Protocol (VoIP) applications, localgaming, Internet gaming, email, instant messaging, multimedia messaging,web browsing, audio/video recording, audio/video playback, audio/videodownloading, playing of streaming audio/video, office applications suchas databases, spreadsheets, word processing, presentation creation andprocessing and other voice and data applications. In conjunction withthese applications, the real-time data 26 includes voice, audio, videoand multimedia applications including Internet gaming, etc. Thenon-real-time data 24 includes text messaging, email, web browsing, fileuploading and downloading, etc.

In an embodiment of the present invention, the communication device 10includes an integrated circuit, such as a combined voice, data and RFintegrated circuit that includes one or more features or functions ofthe present invention. Such integrated circuits shall be described ingreater detail in association with FIGS. 3-15 that follow.

FIG. 2 is a schematic block diagram of an embodiment of anothercommunication system in accordance with the present invention. Inparticular, FIG. 2 presents a communication system that includes manycommon elements of FIG. 1 that are referred to by common referencenumerals. Communication device 30 is similar to communication device 10and is capable of any of the applications, functions and featuresattributed to communication device 10, as discussed in conjunction withFIG. 1. However, communication device 30 includes two separate wirelesstransceivers for communicating, contemporaneously, via two or morewireless communication protocols with data device 32 and/or data basestation 34 via RF data 40 and voice base station 36 and/or voice device38 via RF voice signals 42.

FIG. 3 is a schematic block diagram of an embodiment of an integratedcircuit in accordance with the present invention. In particular, a voicedata RF integrated circuit (IC) 50 is shown that implementscommunication device 10 in conjunction with microphone 60,keypad/keyboard 58, memory 54, speaker 62, display 56, camera 76,antenna interface 52 and wireline port 64. In addition, voice data RF IC50 includes a transceiver 73 with RF and baseband modules for formattingand modulating data into RF real-time data 26 and non-real-time data 24and transmitting this data via an antenna interface 72 and antenna.Further, voice data RF IC 50 includes an input/output module 71 withappropriate encoders and decoders for communicating via the wirelineconnection 28 via wireline port 64, an optional memory interface forcommunicating with off-chip memory 54, a codec for encoding voicesignals from microphone 60 into digital voice signals, a keypad/keyboardinterface for generating data from keypad/keyboard 58 in response to theactions of a user, a display driver for driving display 56, such as byrendering a color video signal, text, graphics, or other display data,and an audio driver such as an audio amplifier for driving speaker 62and one or more other interfaces, such as for interfacing with thecamera 76 or the other peripheral devices.

Off-chip power management circuit 95 includes one or more DC-DCconverters, voltage regulators, current regulators or other powersupplies for supplying the voice data RF IC 50 and optionally the othercomponents of communication device 10 and/or its peripheral devices withsupply voltages and or currents (collectively power supply signals) thatmay be required to power these devices. Off-chip power managementcircuit 95 can operate from one or more batteries, line power and/orfrom other power sources, not shown. In particular, off-chip powermanagement module can selectively supply power supply signals ofdifferent voltages, currents or current limits or with adjustablevoltages, currents or current limits in response to power mode signalsreceived from the voice data RF IC 50. Voice Data RF IC 50 optionallyincludes an on-chip power management circuit 95′ for replacing theoff-chip power management circuit 95.

In an embodiment of the present invention, the voice data RF IC 50 is asystem on a chip integrated circuit that includes at least oneprocessing device. Such a processing device, for instance, processingmodule 225, may be a microprocessor, micro-controller, digital signalprocessor, microcomputer, central processing unit, field programmablegate array, programmable logic device, state machine, logic circuitry,analog circuitry, digital circuitry, and/or any device that manipulatessignals (analog and/or digital) based on operational instructions. Theassociated memory may be a single memory device or a plurality of memorydevices that are either on-chip or off-chip such as memory 54. Such amemory device may be a read-only memory, random access memory, volatilememory, non-volatile memory, static memory, dynamic memory, flashmemory, and/or any device that stores digital information. Note thatwhen the Voice Data RF IC 50 implements one or more of its functions viaa state machine, analog circuitry, digital circuitry, and/or logiccircuitry, the associated memory storing the corresponding operationalinstructions for this circuitry is embedded with the circuitrycomprising the state machine, analog circuitry, digital circuitry,and/or logic circuitry.

In operation, the voice data RF IC 50 executes operational instructionsthat implement one or more of the applications (real-time ornon-real-time) attributed to communication devices 10 and 30 asdiscussed in conjunction with FIGS. 1 and 2. Further, RF IC 50 includesan auto calibrating RF transceiver 73 in accordance with the presentinvention, as will be discussed in greater detail in association withthe description that follows, and particularly in conjunction with FIGS.5-15.

FIG. 4 is a schematic block diagram of another embodiment of anintegrated circuit in accordance with the present invention. Inparticular, FIG. 4 presents a communication device 30 that includes manycommon elements of FIG. 3 that are referred to by common referencenumerals. Voice data RF IC 70 is similar to voice data RF IC 50 and iscapable of any of the applications, functions and features attributed tovoice data RF IC 50 as discussed in conjunction with FIG. 3. However,voice data RF IC 70 includes two separate wireless 73 and 75 forcommunicating, contemporaneously, via two or more wireless communicationprotocols via RF data 40 and RF voice signals 42.

In operation, the voice data RF IC 70 executes operational instructionsthat implement one or more of the applications (real-time ornon-real-time) attributed to communication device 10 as discussed inconjunction with FIG. 1. Further, RF IC 70 includes two auto calibratingRF transceivers 73 and 75 in accordance with the present invention, aswill be discussed in greater detail in association with the descriptionthat follows, and particularly in conjunction with FIGS. 5-15.

FIG. 5 is a schematic block diagram of an RF transceiver 125, such astransceiver 73 or 75, which may be incorporated in communication devices10 and/or 30. The RF transceiver 125 includes an RF transmitter 129, andan RF receiver 127. The RF receiver 127 includes a RF front end 140, adown conversion module 142, a receiver equalization module 182 and areceiver processing module 144. The RF transmitter 129 includes atransmitter processing module 146, a digital up conversion module 148, atransmitter equalization module 180 and a radio transmitter front-end150.

As shown, the receiver and transmitter are each coupled to respectiveantennas through off-chip antenna interfaces 171 and 177 to produceoutbound RF signal 170 and to couple inbound signal 152 to producereceived signal 153. While each antenna is represented as a singleantenna element, the receiver and transmitter may each employ multipleantennas such as a phased array or other multi-antenna configuration, orshare a multiple antenna structure that includes two or more antennas.In another embodiment, the receiver and transmitter may share a multipleinput multiple output (MIMO) antenna structure that includes a pluralityof antennas. Each of these antennas may be fixed, programmable, anantenna array or other antenna configuration. Also, the antennastructure of the wireless transceiver may depend on the particularstandard(s) to which the wireless transceiver is compliant and theapplications thereof.

In operation, the transmitter receives outbound data 162 from a hostdevice or other source via the transmitter processing module 146. Thetransmitter processing module 146 processes the outbound data 162 inaccordance with a selected wireless communication protocol (e.g., IEEE802.11 or other wireless local area network (WLAN) protocol, Bluetooth,RFID, GSM, GPRS, EDGE, CDMA, et cetera) to produce processed data suchas baseband or low intermediate frequency (IF) transmit (TX) signals 164and generates a control signal 169 that indicates the selected one ofthe plurality of protocols. The baseband or low IF TX signals 164 may bedigital baseband signals (e.g., have a zero IF) or digital low IFsignals, where the low IF typically will be in a frequency range of onehundred kilohertz to a few megahertz. Note that the processing performedby the transmitter processing module 146 includes, but is not limitedto, scrambling, encoding, puncturing, mapping, modulation, and/ordigital baseband to IF conversion. Further note that the transmitterprocessing module 146 may be implemented using a shared processingdevice, individual processing devices, or a plurality of processingdevices and may further include memory. Such a processing device may bea microprocessor, micro-controller, digital signal processor,microcomputer, central processing unit, field programmable gate array,programmable logic device, state machine, logic circuitry, analogcircuitry, digital circuitry, and/or any device that manipulates signals(analog and/or digital) based on operational instructions. The memorymay be a single memory device or a plurality of memory devices. Such amemory device may be a read-only memory, random access memory, volatilememory, non-volatile memory, static memory, dynamic memory, flashmemory, and/or any device that stores digital information. Note thatwhen the processing module 146 implements one or more of its functionsvia a state machine, analog circuitry, digital circuitry, and/or logiccircuitry, the memory storing the corresponding operational instructionsis embedded with the circuitry comprising the state machine, analogcircuitry, digital circuitry, and/or logic circuitry.

The up conversion module 148 includes a digital-to-analog conversion(DAC) module, a filtering and/or gain module, and a mixing section. TheDAC module converts the baseband or low IF TX signals 164 from thedigital domain to the analog domain. The filtering and/or gain modulefilters and/or adjusts the gain of the analog signals prior to providingit to the mixing section. The mixing section converts the analogbaseband or low IF signals into up converted signals 166 based on atransmitter local oscillation 168.

The radio transmitter front end 150 includes a power amplifier and mayalso include a transmit filter module. The power amplifier amplifies thedigital up converted signals 166 to produce outbound RF signals 170,which may be filtered by the transmitter filter module, if included. Theantenna structure transmits the outbound RF signals 170 to a targeteddevice such as a RF tag, base station, an access point and/or anotherwireless communication device via an antenna interface 171 coupled to anantenna that provides impedance matching and optional bandpass or notchfiltration. Radio transmitter front end 150 produces a transmit signalfrom the digital up-converted signal in accordance with the selected oneof the plurality of protocols such as GSM, EDGE, CDMS, WLAN, GPRS, etc.

The receiver receives inbound RF signals 152 via the antenna andoff-chip antenna interface 171 that operates to process the inbound RFsignal 152 into received signal 153 for the receiver front-end 140. Ingeneral, antenna interface 171 provides impedance matching of antenna tothe RF front-end 140 and optional bandpass filtration of the inbound RFsignal 152.

The down conversion module 70 includes a mixing section, an analog todigital conversion (ADC) module, and may also include a filtering and/orgain module. The mixing section converts the desired RF signal 154 intoa down converted signal 156 that is based on a receiver localoscillation 158, such as an analog baseband or low IF signal. The ADCmodule converts the analog baseband or low IF signal into a digitalbaseband or low IF signal. The filtering and/or gain module high passand/or low pass filters the digital baseband or low IF signal to producea baseband or low IF signal 156. Note that the ordering of the ADCmodule and filtering and/or gain module may be switched, such that thefiltering and/or gain module is an analog module.

The receiver processing module 144 processes the baseband or low IFsignal 156 in accordance with a particular wireless communicationstandard (e.g., IEEE 802.11, Bluetooth, RFID, GSM, CDMA, et cetera) toproduce inbound data 160. The processing performed by the receiverprocessing module 144 includes, but is not limited to, digitalintermediate frequency to baseband conversion, demodulation, demapping,depuncturing, decoding, and/or descrambling. Note that the receiverprocessing modules 144 may be implemented using a shared processingdevice, individual processing devices, or a plurality of processingdevices and may further include memory. Such a processing device may bea microprocessor, micro-controller, digital signal processor,microcomputer, central processing unit, field programmable gate array,programmable logic device, state machine, logic circuitry, analogcircuitry, digital circuitry, and/or any device that manipulates signals(analog and/or digital) based on operational instructions. The memorymay be a single memory device or a plurality of memory devices. Such amemory device may be a read-only memory, random access memory, volatilememory, non-volatile memory, static memory, dynamic memory, flashmemory, and/or any device that stores digital information. Note thatwhen the receiver processing module 144 implements one or more of itsfunctions via a state machine, analog circuitry, digital circuitry,and/or logic circuitry, the memory storing the corresponding operationalinstructions is embedded with the circuitry comprising the statemachine, analog circuitry, digital circuitry, and/or logic circuitry.

The processing module 225 generates control signals 169 that command theRF receiver 127 and RF transmitter into a selected one of a plurality ofmodes including a receive calibration mode where the RF receiver 127 iscalibrated based on a calibration signal from the transmitter 129 and atransmit calibration mode where the RF transmitter 129 is calibratedbased on receiver feedback signals 186 received from RF receiver 127. Ineach of these modes the transmit signal 155 is received by the RFreceiver 127, either through the respect transmit and receive antennascoupled to antenna interfaces 171 and 177 or through a separateattenuated coupling between the radio transmitter front-end 150 and theRF front-end 140 that is activated when the control signals 169 indicatethat either a transmit calibration mode or a receive calibration modehas been selected.

In operation, processing module 225 generates control signals 169 thatinclude a control signal that indicates a receive calibration mode. Whenin this receive calibration mode, RF transmitter 129 generates atransmit signal 155 that includes a first calibration signal. RFreceiver 127 receives a received signal 153 that includes the firstcalibration signal and generates at least one receiver equalizationparameter for equalizing the RF receiver in response to receiverfeedback signals. In another mode of operation, control signal 169 caninclude a control signal that indicates a transmit calibration mode.During this transit calibration mode, RF transceiver 129 generates asecond calibration signal and RF receiver 127 receives the receivedsignal 153 that includes the second calibration signal and generatesreceiver feedback signals 186 in response thereto. RF transmitter 129then generates at least one transmitter equalization parameter forequalizing the RF transmitter in response to the receiver feedbacksignals 186. In this fashion, a calibration signal from the RFtransmitter 129 can be used to calibrate the RF receiver 127 and, oncecalibrated, receiver feedback signals 186 generated by theequalized/calibrated RF receiver 127 in response to a second calibrationsignal can be used to equalize (calibrate) the RF transmitter 129.Further details regarding the operation of receiver equalization module182 and transmitter equalization module 180 are presented in conjunctionwith FIGS. 6 and 7 that follow.

FIG. 6 is a schematic block diagram of a transmitter equalization module180 in accordance with an embodiment of the present invention. Inparticular, a transmit equalizer module 180 is shown that that includesa calibration signal generator 200 and a transmit equalizer module 210.In an embodiment of the present invention, in receive calibration mode,the calibration signal generator 200 generates calibration signals 202such as modulated data signal having known data or other test sequencethat is generated at RF frequencies and is passed to radio transmitterfront-end 150 to produce transmit signal 155 or is generated at basebandor at IF frequencies and passed to up conversion module 148 to generatetransmit signal 155 through radio transmitter front-end 150. Thiscalibration signal generator 200 can be implemented with a signalgenerator that is separate from transmitter processing module 146 and/orup conversion module 148 (as shown) or using common or shared componentsof transmitter processing module 146 and/or up conversion module 148. Intransmit calibration mode, the calibration signal generator 200 alsogenerates calibration signals 202 such as modulated data signal havingknown data or other test sequence that is generated at RF frequenciesand is passed to radio transmitter front-end 150 to produce transmitsignal 155 or is generated at baseband or at IF frequencies and passedto up conversion module 148 to generate transmit signal 155 throughradio transmitter front-end 150. These calibration signals may be thesame as used in receive calibration mode or different depending on thetype of equalization employed by the RF receiver 127 and RF transmitter129, and other design considerations.

Transmit equalizer module 210 generates the at least one transmitterequalization parameter 212 in response to the receiver feedback signals.In an embodiment of the present invention, the RF receiver 127 usesmixed signal processing and the receiver feedback signals 186 indicatean in-phase gain and a quadrature-phase gain of the RF receiver 127.This information can be used by transmit equalizer module 210 to adjustan in-phase gain and/or a quadrature-phase gain of the RF transmitter129 in the event that the RF transmitter uses mixed signal processingand/or produces phase coherent signaling. While the embodiment abovedescribes two adjustments, a greater number of adjustments are possibleto correct the magnitudes and phases of a greater number of transmittedsignals in a constellation pattern to a preferred alignment.

In a further embodiment of the present invention, the receiver feedbacksignals 186 indicate a frequency response of the RF receiver 127including the spectrum of the receive signal 153. This frequencyspectrum information can be used to derive transmitter equalizationparameters 212 that equalizes the frequency response of the RFtransmitter 129. For instance, transmitter 129 can include a channelequalization filter such as an finite impulse response (FIR) filter orother filter having filter coefficients that are based on thetransmitter equalization parameters 212. Similarly, the receiverfeedback signals 186 can indicate an impulse response of the RF receiver127 and the transmitter equalization parameters 212 can equalizes theimpulse response of the RF transmitter 129.

Alternatively or in addition, the receiver feedback signals 186 canindicate a timing parameter of the RF receiver such as a bit time, aframe interval, a timing offset or other timing parameter, and thetransmitter equalization parameters 212 can equalize the timingparameter of the RF transmitter 129 by adjusting the correspondingtiming.

In an embodiment of the present invention, the transmit equalizer module210 can be implemented using a shared processing device, individualprocessing devices, or a plurality of processing devices and may furtherinclude memory. Such a processing device may be a microprocessor,micro-controller, digital signal processor, microcomputer, centralprocessing unit, field programmable gate array, programmable logicdevice, state machine, logic circuitry, analog circuitry, digitalcircuitry, and/or any device that manipulates signals (analog and/ordigital) based on operational instructions. The memory may be a singlememory device or a plurality of memory devices. Such a memory device maybe a read-only memory, random access memory, volatile memory,non-volatile memory, static memory, dynamic memory, flash memory, and/orany device that stores digital information. Note that when the transmitequalizer module 210 implements one or more of its functions via a statemachine, analog circuitry, digital circuitry, and/or logic circuitry,the memory storing the corresponding operational instructions isembedded with the circuitry comprising the state machine, analogcircuitry, digital circuitry, and/or logic circuitry.

FIG. 7 is a schematic block diagram of a receiver equalization module184 in accordance with an embodiment of the present invention. Inparticular receiver equalization module 184 includes a feedback signalgenerator 220 and a receiver equalization module 224. Feedback signalgenerator 220 generates the feedback signals 186, such as in-phase andquadrate phase gains, frequency and/or impulse responses of thereceiver, the spectrum or response of received signals, magnitude andphase errors in the one or more signals in a constellation pattern,timing errors, etc. based on an analysis of one or more parameters 220of the RF receiver 127 and the various intermediate RF, IF and basebandsignals produced thereby.

Receiver equalizer module 224 generates the at least one receiverequalization parameter 226 in response to the receiver feedback signals184. In an embodiment of the present invention, the receiver feedbacksignals 186 indicate an in-phase gain and a quadrature-phase gain of theRF receiver 127. This information can be used by receive equalizermodule 224 to adjust an in-phase gain and/or a quadrature-phase gain ofthe RF receiver 127. While the embodiment above describes twoadjustments, a greater number of adjustments are possible to correct themagnitudes and phases of a greater number of transmitted signals in aconstellation pattern to a preferred alignment.

In a further embodiment of the present invention, the receiver feedbacksignals 186 indicate a frequency response of the RF receiver 127including the spectrum of the receive signal 153. This frequencyspectrum information can be used to derive receiver equalizationparameters 224 that equalizes the frequency response of the RF receiver127. For instance, RF receiver 127 can include a channel equalizationfilter such as a finite impulse response (FIR) filter or other filterhaving filter coefficients that are based on the receiver equalizationparameters 226. Similarly, the receiver feedback signals 186 canindicate an impulse response of the RF receiver 127 and the receiverequalization parameters 226 can equalize the impulse response of the RFreceiver 127.

Alternatively or in addition, the receiver feedback signals 186 canindicate a timing parameter of the RF receiver such as a bit time, aframe interval, a timing offset or other timing parameter, and thereceiver equalization parameters 226 can equalize the timing parametersof the RF receiver 127 by adjusting the corresponding timing.

In an embodiment of the present invention the feedback signal generator220 and receiver equalizer module 224 can each be implemented using ashared processing device, individual processing devices, or a pluralityof processing devices and may further include memory. Such a processingdevice may be a microprocessor, micro-controller, digital signalprocessor, microcomputer, central processing unit, field programmablegate array, programmable logic device, state machine, logic circuitry,analog circuitry, digital circuitry, and/or any device that manipulatessignals (analog and/or digital) based on operational instructions. Thememory may be a single memory device or a plurality of memory devices.Such a memory device may be a read-only memory, random access memory,volatile memory, non-volatile memory, static memory, dynamic memory,flash memory, and/or any device that stores digital information. Notethat when the feedback signal generator 220 and receiver equalizermodule 224 implement one or more of its functions via a state machine,analog circuitry, digital circuitry, and/or logic circuitry, the memorystoring the corresponding operational instructions is embedded with thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry.

FIG. 8 is a schematic block diagram of an RF transceiver 125 inaccordance with a further embodiment of the present invention. Thisembodiment is similar to the embodiment presented in conjunction withFIG. 5 with similar elements being referred to by common referencenumerals. In this embodiment however, RF receiver 127 and RF transmitter129 share a single antenna and antenna interface 171. As shown, thereceiver and transmitter are each coupled to an antenna through anoff-chip antenna interface 171 and a transmit/receive switch 175, thatcouples the transmit signal 155 to the antenna to produce outbound RFsignal 170 and couples inbound signal 152 to produce received signal153. The transmit/receive switch 175 operates under the command ofcontrol signals 169 to couple an attenuated version of the transmitsignal 155 as the received signal 153 when the control signals 169indicate either a receiver calibration mode or a transmitter calibrationmode. Further details regarding a possible implementation of transmitreceive switch 175 is described in conjunction with FIGS. 9-11 thatfollow.

FIG. 9 is a schematic block diagram of a transmit/receive switch 175 ina transmit mode in accordance with a further embodiment of the presentinvention. In particular, in transmit mode, switch module 230 oftransmit/receive switch 175 routes the transmit signal 155 to theantenna interface 171 to produce outbound RF signal 170.

FIG. 10 is a schematic block diagram of a transmit/receive switch 175 ina receive mode in accordance with a further embodiment of the presentinvention. In particular, in receive mode, switch module 230 of thetransmit/receive switch 175 routes inbound RF signal 152 to the RFreceiver 127 as received signal 153.

FIG. 11 is a schematic block diagram of a transmit/receive switch 175 ina receiver calibration mode and transmitter calibration mode inaccordance with a further embodiment of the present invention. In eitherthe transmitter or receiver calibration mode, the transmit signal 155 isrouted through the attenuated coupling 232 by the switch module 230 toproduce a received signal 153 that is an attenuated version of thetransmit signal 155. This allows the signal level of the received signal153 to be attenuated to a signal level that avoids overloading the inputof RF receiver 127.

FIG. 12 is a flowchart representation of a method in accordance with anembodiment of the present invention. In particular a method is presentedfor use with one or more features or functions presented in conjunctionwith FIGS. 1-11. In step 400, at least one control signal is generatedthat indicates a receive calibration mode. In step 402, a transmitsignal is generated that includes a first calibration signal when the atleast one control signal indicates the receive calibration mode. In step408, a received signal is received in an RF receiver that includes thefirst calibration signal, when the at least one control signal indicatesthe receive calibration mode. In step 410, at least one receiverequalization parameter is generated based on receiver feedback signals,when the at least one control signal indicates the receive calibrationmode. In step 412, the RF receiver is equalized based on the at leastone receiver equalization parameter, when the at least one controlsignal indicates the receive calibration mode.

In an embodiment of the present invention, the receiver feedback signalsindicate at least one of, an in-phase gain of the RF receiver, and aquadrature-phase gain of the RF receiver, and the at least one receiverequalization parameter can equalize at least one of the in-phase gainand the quadrature-phase gain. Also, the receiver feedback signals canindicate a frequency response of the RF receiver, and the at least onereceiver equalization parameter can equalize the frequency response.Further, the receiver feedback signals can indicate an impulse responseof the RF receiver, and the at least one receiver equalization parametercan equalize the impulse response. In addition, the receiver feedbacksignals indicate a timing parameter of the RF receiver, and the at leastone receiver equalization parameter can equalize the timing parameter.

FIG. 13 is a flowchart representation of a method in accordance with anembodiment of the present invention. In particular a method is presentedfor use with the method of FIG. 12 that includes similar elements thatare referred to by common reference numerals. In addition, the methodincludes step 404 of attenuating the transmit signal to form anattenuated signal and step 406 of coupling the attenuated signal as thereceived signal when the at least one control signal indicates thereceive calibration mode.

FIG. 14 is a flowchart representation of a method in accordance with anembodiment of the present invention. In particular a method is presentedfor use with one or more features or functions presented in conjunctionwith FIGS. 1-13 when the control signal indicates the transmitcalibration mode. In step 500 a second calibration signal is generatedin an RF transmitter. In step 506, the received signal is received thatincludes the second calibration signal in the RF receiver. In step 508,receiver feedback signals are generated in response to the secondcalibration signal. In step 510 at least one transmitter equalizationparameter is generated based on the receiver feedback signals. In step512, the RF transmitter is equalized based on the at least onetransmitter equalization parameter.

In an embodiment of the present invention the receiver feedback signalsindicate at least one of, an in-phase gain of the RF receiver, and aquadrature-phase gain of the RF receiver, and the at least onetransmitter equalization parameter equalizes at least one of an in-phasegain of the RF transmitter and a quadrature-phase gain of the RFtransmitter. Also, the receiver feedback signals can indicate afrequency response of the RF receiver, and the at least one transmitterequalization parameter equalizes the frequency response of the RFtransmitter. In addition, the receiver feedback signals can indicate animpulse response of the RF receiver, and the at least one transmitterequalization parameter equalizes the impulse response of the RFtransmitter. Further, the receiver feedback signals can indicate atiming parameter of the RF receiver, and the at least one transmitterequalization parameter equalizes the timing parameter of the RFtransmitter.

FIG. 15 is a flowchart representation of a method in accordance with anembodiment of the present invention. In particular a method is presentedfor use with the method of FIG. 14 that includes similar elements thatare referred to by common reference numerals. In addition, the methodincludes step 502 of attenuating the transmit signal to form anattenuated signal and step 504 of coupling the attenuated signal as thereceived signal when the at least one control signal indicates thetransmit calibration mode.

As may be used herein, the terms “substantially” and “approximately”provides an industry-accepted tolerance for its corresponding termand/or relativity between items. Such an industry-accepted toleranceranges from less than one percent to fifty percent and corresponds to,but is not limited to, component values, integrated circuit processvariations, temperature variations, rise and fall times, and/or thermalnoise. Such relativity between items ranges from a difference of a fewpercent to magnitude differences. As may also be used herein, theterm(s) “coupled to” and/or “coupling” and/or includes direct couplingbetween items and/or indirect coupling between items via an interveningitem (e.g., an item includes, but is not limited to, a component, anelement, a circuit, and/or a module) where, for indirect coupling, theintervening item does not modify the information of a signal but mayadjust its current level, voltage level, and/or power level. As mayfurther be used herein, inferred coupling (i.e., where one element iscoupled to another element by inference) includes direct and indirectcoupling between two items in the same manner as “coupled to”. As mayeven further be used herein, the term “operable to” indicates that anitem includes one or more of power connections, input(s), output(s),etc., to perform one or more its corresponding functions and may furtherinclude inferred coupling to one or more other items. As may stillfurther be used herein, the term “associated with”, includes directand/or indirect coupling of separate items and/or one item beingembedded within another item. As may be used herein, the term “comparesfavorably”, indicates that a comparison between two or more items,signals, etc., provides a desired relationship. For example, when thedesired relationship is that signal 1 has a greater magnitude thansignal 2, a favorable comparison may be achieved when the magnitude ofsignal 1 is greater than that of signal 2 or when the magnitude ofsignal 2 is less than that of signal 1.

While the transistors discussed above may be field effect transistors(FETs), as one of ordinary skill in the art will appreciate, thetransistors may be implemented using any type of transistor structureincluding, but not limited to, bipolar, metal oxide semiconductor fieldeffect transistors (MOSFET), N-well transistors, P-well transistors,enhancement mode, depletion mode, and zero voltage threshold (VT)transistors.

The present invention has also been described above with the aid ofmethod steps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claimed invention.

The present invention has been described above with the aid offunctional building blocks illustrating the performance of certainsignificant functions. The boundaries of these functional buildingblocks have been arbitrarily defined for convenience of description.Alternate boundaries could be defined as long as the certain significantfunctions are appropriately performed. Similarly, flow diagram blocksmay also have been arbitrarily defined herein to illustrate certainsignificant functionality. To the extent used, the flow diagram blockboundaries and sequence could have been defined otherwise and stillperform the certain significant functionality. Such alternatedefinitions of both functional building blocks and flow diagram blocksand sequences are thus within the scope and spirit of the claimedinvention. One of average skill in the art will also recognize that thefunctional building blocks, and other illustrative blocks, modules andcomponents herein, can be implemented as illustrated or by discretecomponents, application specific integrated circuits, processorsexecuting appropriate software and the like or any combination thereof.

1. A voice, data and RF integrated circuit (IC) comprising: a processingmodule that generates at least one control signal that indicates areceive calibration mode; an RF transmitter, coupled to the processingmodule, that generates a transmit signal that includes a firstcalibration signal when the at least one control signal indicates thereceive calibration mode; and an RF receiver, coupled to the processingmodule, that receives a received signal that includes the firstcalibration signal and that generates at least one receiver equalizationparameter for equalizing the RF receiver in response to receiverfeedback signals, when the at least one control signal indicates thereceive calibration mode.
 2. The voice, data and RF IC of claim 1wherein the RF transmitter includes a transmitter equalization modulehaving a calibration signal generator that generates the firstcalibration signal when the at least one control signal indicates thereceive calibration mode.
 3. The voice, data and RF IC of claim 1wherein the RF receiver includes a receiver equalization module having afeedback signal generator that generates the receiver feedback signalsin response to receiver parameters generated by the RF receiver andfurther having a receiver equalization module that generates the atleast one receiver equalization parameter from the receiver feedbacksignals.
 4. The voice, data and RF IC of claim 3 wherein the receiverfeedback signals indicate at least one of, an in-phase gain of the RFreceiver, and a quadrature-phase gain of the RF receiver, and whereinthe at least one receiver equalization parameter equalizes at least oneof the in-phase gain and the quadrature-phase gain.
 5. The voice, dataand RF IC of claim 3 wherein the receiver feedback signals indicate afrequency response of the RF receiver, and wherein the at least onereceiver equalization parameter equalizes the frequency response.
 6. Thevoice, data and RF IC of claim 3 wherein the receiver feedback signalsindicate an impulse response of the RF receiver, and wherein the atleast one receiver equalization parameter equalizes the impulseresponse.
 7. The voice, data and RF IC of claim 3 wherein the receiverfeedback signals indicate a timing parameter of the RF receiver, andwherein the at least one receiver equalization parameter equalizes thetiming parameter.
 8. The voice, data and RF IC of claim 1 wherein the atleast one control signal indicates a transmit calibration mode, and whenthe at least one control signal indicates the transmit calibration mode,the RF transceiver generates a second calibration signal, the RFreceiver receives the receiver signal that includes the secondcalibration signal and generates receiver feedback signals in responsethereto, and the RF transmitter generates at least one transmitterequalization parameter for equalizing the RF transmitter in response tothe receiver feedback signals.
 9. The voice, data and RF IC of claim 8wherein the RF transmitter includes a transmit equalizer module thatgenerates the at least one transmitter equalization parameter inresponse to the receiver feedback signals.
 10. The voice, data and RF ICof claim 9 wherein the receiver feedback signals indicate at least oneof, an in-phase gain of the RF receiver, and a quadrature-phase gain ofthe RF receiver, and wherein the at least one transmitter equalizationparameter equalizes at least one of an in-phase gain of the RFtransmitter and a quadrature-phase gain of the RF transmitter.
 11. Thevoice, data and RF IC of claim 9 wherein the receiver feedback signalsindicate a frequency response of the RF receiver, and wherein the atleast one transmitter equalization parameter equalizes the frequencyresponse of the RF transmitter.
 12. The voice, data and RF IC of claim 9wherein the receiver feedback signals indicate an impulse response ofthe RF receiver, and wherein the at least one transmitter equalizationparameter equalizes the impulse response of the RF transmitter.
 13. Thevoice, data and RF IC of claim 9 wherein the receiver feedback signalsindicate a timing parameter of the RF receiver, and wherein the at leastone transmitter equalization parameter equalizes the timing parameter ofthe RF transmitter.
 14. The voice, data and RF IC of claim 9 furthercomprising: an attenuated coupling, coupled to the RF transmitter andthe RF receiver, that attenuates the transmit signal to form anattenuated signal and that couples the attenuated signal as the receivedsignal when the at least one control signal indicates the transmitcalibration mode.
 15. The voice, data and RF IC of claim 1 furthercomprising: an attenuated coupling, coupled to the RF transmitter andthe RF receiver, that attenuates the transmit signal to form anattenuated signal and that couples the attenuated signal as the receivedsignal when the at least one control signal indicates the receivecalibration mode.
 16. A method comprising: generating at least onecontrol signal that indicates a receive calibration mode; generating atransmit signal that includes a first calibration signal when the atleast one control signal indicates the receive calibration mode;receiving a received signal in an RF receiver that includes the firstcalibration signal, when the at least one control signal indicates thereceive calibration mode; generating at least one receiver equalizationparameter based on receiver feedback signals, when the at least onecontrol signal indicates the receive calibration mode; and equalizingthe RF receiver based on the at least one receiver equalizationparameter, when the at least one control signal indicates the receivecalibration mode.
 17. The method claim 16 wherein the receiver feedbacksignals indicate at least one of, an in-phase gain of the RF receiver,and a quadrature-phase gain of the RF receiver, and wherein the at leastone receiver equalization parameter equalizes at least one of thein-phase gain and the quadrature-phase gain.
 18. The method claim 16wherein the receiver feedback signals indicate a frequency response ofthe RF receiver, and wherein the at least one receiver equalizationparameter equalizes the frequency response.
 19. The method claim 16wherein the receiver feedback signals indicate an impulse response ofthe RF receiver, and wherein the at least one receiver equalizationparameter equalizes the impulse response.
 20. The method claim 16wherein the receiver feedback signals indicate a timing parameter of theRF receiver, and wherein the at least one receiver equalizationparameter equalizes the timing parameter.
 21. The method of claim 16further comprising: attenuating the transmit signal to form anattenuated signal; and coupling the attenuated signal as the receivedsignal when the at least one control signal indicates the receivecalibration mode.
 22. The method claim 16 wherein the at least onecontrol signal indicates a transmit calibration mode, the method furthercomprising; when the at least one control signal indicates the transmitcalibration mode, generating a second calibration signal in an RFtransmitter; receiving the received signal that includes the secondcalibration signal in the RF receiver; generating receiver feedbacksignals in response to the second calibration signal; generating atleast one transmitter equalization parameter based on the receiverfeedback signals; and equalizing the RF transmitter based on the atleast one transmitter equalization parameter.
 23. The method of claim 22wherein the receiver feedback signals indicate at least one of, anin-phase gain of the RF receiver, and a quadrature-phase gain of the RFreceiver, and wherein the at least one transmitter equalizationparameter equalizes at least one of an in-phase gain of the RFtransmitter and a quadrature-phase gain of the RF transmitter.
 24. Themethod of claim 22 wherein the receiver feedback signals indicate afrequency response of the RF receiver, and wherein the at least onetransmitter equalization parameter equalizes the frequency response ofthe RF transmitter.
 25. The method of claim 22 wherein the receiverfeedback signals indicate an impulse response of the RF receiver, andwherein the at least one transmitter equalization parameter equalizesthe impulse response of the RF transmitter.
 26. The method of claim 22wherein the receiver feedback signals indicate a timing parameter of theRF receiver, and wherein the at least one transmitter equalizationparameter equalizes the timing parameter of the RF transmitter.
 27. Themethod of claim 22 further comprising: attenuating the transmit signalto form an attenuated signal; and coupling the attenuated signal as thereceived signal when the at least one control signal indicates thetransmit calibration mode.